i have 4 analog signal patterns i want to check if the reads belongs to which pattern...so that i will make a database for each pattern then check if the new signal belong to the pattern with acceptable error rate

"same time" is subjective. It sounds like you want to do this process with respect to the Arduino. Unfortunately, the Arduino doesn't have a "compare array of values to withing a specific threshold" instruction.

Time scales are relative...To the Arduino, the "same time" is on the order of microseconds.To the human eye, the "same time" is on the order of 100's of milliseconds.To a Physicists I work with, the "same time" is on the order of picoseconds (or smaller).To a Geologist, the "same time" is on the order of hundreds of years (or larger)...